The invention relates to a rotary test machine. Such a rotary piston machine is known (German patent 4241320) as a pump, compressor or motor, for which the ridges of teeth of a rotating driving parts, in order to limit the working spaces, run on a cycloid surface of an also toothed driven part, driving the latter. The aforementioned working spaces, which are increased or decreased in size for their work during the rotation of the parts, in order to produce the delivery action on a medium, are formed between the teeth of the driving and driven parts.
It has also already been proposed (patent application DE 103 35 939.7 of Aug. 2, 2003) that a portion of the machine housing be mounted in a “floating manner”, in order to be able to equalize gap losses and the like better by these means. However, such a floating arrangement has the disadvantage that, at the expense of a decrease in the losses through the gap, the danger of imbalances arises. The significance of this disadvantage depends on the practical use of the object, the rpm then actually employed and the pressure aimed for playing an important roll.